Female contact for electrical outlet receptacle



Dec. 20, 1960 u w 2,965,869

FEMALE CONTACT FOR ELECTRICAL OUTLET RECEPTACLE Filed Sept. 24, 1959INVENTOR. Lou/5 Luau/e 2,965,869 Patented Dec. 20, 1960 FEMALE CONTACTFOR ELECTRICAL OUTLET RECEPTACLE Louis Ludwig, New York, NY.

Eagle Electric Mfg. (10., line, 23-10 Bridge Plaza 8., NY.)

Long Island City 1,

Filed Sept. 24, 1959, Ser. No. 842,091 4 Claims. (Cl. 339--33) Theinvention relates to female contacts for electrical receptacles.

It is an object of my invention to provide an improved female contactwhich, although of an extremely simple unitary construction that is easyand inexpensive to fabricate, affords a novel and unusually goodengagement with a male contact blade.

It is another object of my invention to provide a contact of thecharacter described which utilizes a unique combination of forces tocreate an excellent electrical engagement that effectively willwithstand long and rough usage.

It is another object of my invention to provide a contact of thecharacter described which will efiiciently engage both tandem andparallel blades.

Other objects of my invention in part will be obvious and in part willbe pointed out hereinnafter.

My invention accordingly consists in the features of construction,combinations of elements and arrangements of parts which will beexemplified in the device hereinafter illustrated and described and ofwhich the scope of application will be indicated in the appended claims.

In the accompanying. drawings in which is shown one of the variouspossible embodiments of my invention,

Fig. 1 is a front view of a duplex electric receptacle in which thereare incorporated female contacts constructed in accordance with myinvention;

Fig. 2 is a sectional view taken substantially along the line 2-2 ofFig. 1;

Fig. 3 is a sectional view taken substantially along the line 3-3 ofFig. 2, and showing the receptacle as it appears with the top housingremoved;

Fig. 4 is a sectional view taken substantially along the line 4-4 ofFig. 3;

Fig. 5 is an elevational view of one of the contact pieces;

Fig. 6 is a sectional view taken line 6-6 of Fig. 5; and

Fig. 7 is a perspective View of a portion of one of the contact pieces,to wit, the female contact, which constitutes the novel feature of thepresent invention.

Referring now in detail to the drawings, the reference numeral 10denotes a duplex electric receptacle which is conventional except forthe female contacts. Said receptacle includes a casing comprising twoparts, to wit, a top housing 12 and a bottom housing 14 both of whichare fabricated from electrically non-conductive material that isresistant to mild heat, a typical material being a phenolformaldehydecondensation resin. The two housing parts are attached to one another inany suitable fashion, for instance by a screw 16 the head of which isseated in an aperture in the bottom housing and the shank of which isscrewed into a tapped well in the top housing.

Clamped between the two housing parts is the usual mounting strap 18.

The top housing is formed to provide two identical outlets 2d, 22 eachof which is adapted to have inserted substantially along the therein apair of male contact blades. For this purpose each outlet includes twoT-shaped through openings 24,

as is customary. Beneath each of the T-shaped openings in each outletthe two housing parts define a chamber 26, so that in all there are fourchambers in the receptacle The chamber 26 of any given outlet isconnected to the matching chamber of the other outlet by a lowpassageway 28. The chambers areinternally shaped to accommodate the endsof contact pieces 30. There are two contact pieces 30 in the receptacle,each having at each end thereof a female contact. Each female contact islocated in a different chamber 26.

Each contact piece 30 is fabricated from a single strip of fiatresilient sheet metal of good electrical conductivity, e.g., springbrass or phosphor bronze. Typically, each contact piece has a shank 32from the opposite ends of which the female contacts 34 extend. Themiddle of each shank is snugly received in a different passageway 28.

Each shank includes on opposite sides of its center a slit 36 whichextends parallel to the longitudinal axis of the contact piece and isdisposed between the lateral edges thereof. The material between eachslit and a lateral edge, e.g., the outer lateral edge, of the shank isformed with a transverse slit 38 extending from the slit 36 to saidlongitudinal edge, so as to provide a pair of resilient tongues 40, 42.The tongues are shaped so that in relaxed positions their tips areslanted into the chamber to define between them a slot 44 which isslightly smaller than a bare solid conductor such as is commonly used inhouse wiring. Thereby, when insulation is stripped from the conductorand the conductor thrust into the slot 44, it will force apart thetongues 40, 42 which will bite into the conductor and prevent the samefrom being withdrawn.

Such a conductor is inserted into the slot through an opening 46 in thelower wall of the bottom housing 14. Another opening 48 in .said wallbeneath the tongue 40 is included to permit the conductor to be releasedby forcing the tongue 40 away from such conductor as by inserting a nailthrough the opening 48 to bear against the tongue 40. This arrangementis well known and forms no part of my invention.

In accordance withthe present invention I form the female contacts 34 toan unusual and special construction whereby to create contacts which arecapable not only of receiving either tandem or parallel male contactblades with the use of a minimum of material, but also of engaging aparallel blade in a manner such as to provide an unusually goodelectrical contact therewith.

Each female contact 34 includes first and second fiat legs 50, 52 in onepiece with and extending upwardly from the shank 32. The legs aresubstantially in a common plane, the slight deviation from coplanaritybeing described in detail hereinafter. Said two legs are approximatelyparallel, that is to say, their inner edges 54, 56 which face oneanother are in substantial parallelism. Actually, these edges are notexactly parallel, but converge from near the shank 32 upwardly as bestcan be seen by inspection of Fig. 6. Thereby, said edges form, ineffect, a slot 58 extending upwardly from the shank. The outer end ofthe slot is flared by provision of outwardly diverging camming portions60, 62 on the edges 54, 56. Said camming portions are included tofacilitate entry of a male blade therebetween.

The second leg 52 is formed at its upper tip with a retroverted bend 64from which there extends downwardly a third flat leg 66 that issubstantially parallel to the second leg 52. Phrased differently, thesecond and third legs 52, 66, together with the retroverted bend 64,define a U-shape (see Fig. 5). At the bottom tip of the third leg 66 Iprovide a fiat cross member 68 in one piece with said leg 66. Extendingupwardly from the cross member is a fourth fiat leg 70 in substantiallythe same plane as the third leg 66 and substantially parallel to thefirst leg 50. The inner edges of the third and fourth legs 66, 70 areshaped in exactly the same manner as the inner edges 54, 56 of the firstand second legs 50, 52, so that these two pairs of inner edges are inregistry. Said inner edges of the third and fourth legs 66, 70 define asecond upwardly extending slot 71 of the same shape and dimensions asthe slot 58 and in registry therewith.

Desirably, the first and fourth legs 50, 70 slightly converge upwardlytoward one another (see Fig. 5) out of the planes of the second andthird legs 52, 66 and at their outer extremities flare apart tofacilitate entry of a tandem male contact blade. The first and fourthlegs provide between them a third slot 72 at right angles to andintersecting a fourth slot 74 defined by the registered slots 58, 71.

The aforesaid fourth slot 74 is adapted to receive a parallel malecontact blade, while the third slot 72 is adapted to receive a tandemmale contact blade. It will be apparent that the female contacts are solocated in their respective chambers 26 that the said third and fourthslots of each will be located directly below and in registry with theassociated parts of a T-opening 24 in the top housing 12. Thereby, wheneither a parallel or tandem blade is inserted in the proper portion of aT-shaped opening, it will enter the correct slot of the contact. Atandem blade will enter the .slot 72 and a parallel blade will enter theslot 74. Thereby, with an extremely simple construction of femalecontact utilizing a fiat strip whose width does not exceed thatnecessary for the shank 32 I am able to form a female contact capable ofefiiciently receiving either a tandem or a parallel blade.

I have found that the engagement effected between a parallel blade andthe novel female contact is unusually good and surpasses that whichwould be secured if the third slot 72 were omitted, this being due tothe combination of forces which are created upon the insertion of such ablade and which arises from the presence of said slot 72. When aparallel blade enters the fourth slot 74, instead of merely flexing thepair of first and fourth legs 50, 70 away from the pair of second andthird legs 52, 66, the blade additionally twists the legs 52, 70 abouttheir bases, so that the resultant force is a combination of compressionand torque. This complex combined force acting upon a parallel blade hasbeen found to create a particularly good electrical contact whichwithstands long and hard usage.

It thus will be seen that I have provided a female electrical contactwhich achieves the several objects of my invention and is well adaptedto meet the conditions of practical use.

As various possible embodiments might be made of my invention and asvarious changes might be made in the embodiment above set forth, it isto be understood that all matter herein described or shown in theaccompanying drawings is to be interpreted as illustrative and not in alimiting sense.

Having thus described my invention, I claim as new, and desire to secureby Letters Patent:

1. A female contact at an end of a wide flat shank, said contactcomprising a first leg, a second leg, a third leg, a fourth leg, aretroverted bend and a cross member,

all in one piece with the shank, said first and second legs extendingupwardly from the end of the shank in substantially parallelrelationship, the upper end of the first leg being free, the retrovertedbend connecting the upper ends of the second and third legs, the crossmember connecting the lower ends of the third and fourth legs, the upperend of the fourth leg being free, the third leg being substantiallyparallel to the second leg in a direction transverse to the direction ofparallelism of the first and second legs, the fourth leg beingsubstantially parallel to the third leg in a direction parallel to thedirection of parallelism of the first and second legs, the fourth legbeing substantially parallel to the first leg in a direction parallel tothe direction of parallelism of the second and third legs, the first andsecond legs defining between them a first upwardly extending slot, thethird and fourth legs defining between them a second upwardly extendingslot, said first and second slots being registered and mutually forminga third upwardly extending slot, said first and fourth members definingbetween them a fourth upwardly extending slot running transversely intothe third upwardly extending slot between the first and second upwardlyextending slots.

2. A contact as set forth in claim 1 wherein all the legs are fiat,wherein the first and second legs are in substantially a first commonplane and wherein the third and fourth legs are in substantially asecond common plane that is parallel to the first common plane.

3. A female contact comprising a first leg, a second leg, a third leg, afourth leg, a retroverted bend, a first cross member, and a second crossmember, all in one piece, said first and second legs extending upwardlyfrom the end of the first cross member in substantially parallelrelationship, the upper end of the first leg being free, the retrovertedbend connecting the upper ends of the second and third legs, the secondcross member connecting the lower ends of the third and fourth legs, theupper end of the fourth leg being free, the third leg beingsubstantially parallel to the second leg in a direction transverse tothe direction of parallelism of the first and second legs, the fourthleg being substantially parallel to the third leg in a directionparallel to the direction of parallelism of the first and second legs,the fourth leg being substantially parallel to the firstleg in adirection parallel to the direction of parallelism of the second andthird legs, the first and second legs defining between them a firstupwardly extending slot, the third and fourth legs defining between thema second upwardly extending slot, said first and second slots beingregistered and mutually forming a third upwardly extending slot, saidfirst and fourth members defining between them a fourth upwardlyextending slot running transversely into the third upwardly extendingslot between the first and second upwardly extending slots.

4. A contact as set forth in claim 3 wherein all the legs are flat,wherein the first and second legs are in substantially a first commonplane and wherein the third and fourth legs are in substantially asecond common plane that is parallel to the first common plane.

References Cited in the file of this patent UNITED STATES PATENTS1,635,056 Paiste July 5, 1927 2,076,694 Bertschi Apr. 13, 1937 2,865,010Taylor Dec. 16, 1958

